When you think of the world's largest eyes, you might picture the giant squid. And you wouldn't be far off—those legendary deep-sea creatures do have absolutely massive eyes, roughly the size of dinner plates at 10 inches across. But there's a twist: they're not the record holder.

That honor goes to their lesser-known cousin, the colossal squid. This Antarctic giant sports eyes that can reach 11 to 12 inches in diameter—about the size of a basketball. To put that in perspective, a blue whale (the largest animal that has ever lived) has eyes only about 4 inches wide. A swordfish, which has the biggest eyes of any fish, maxes out at 3.5 inches. The colossal squid's pupil alone is bigger than that entire eyeball.

Why the Confusion?

The mix-up is understandable. For decades, the giant squid was the poster child for deep-sea mysteries. It was featured in countless documentaries, novels, and maritime legends. The colossal squid, on the other hand, remained largely unknown until relatively recently.

Scientists didn't even confirm the colossal squid's existence until the late 20th century, and complete specimens are extremely rare. In fact, the first-ever footage of a live colossal squid in its natural habitat wasn't captured until March 2025, when researchers filmed one near the South Sandwich Islands.

Built for the Abyss

So why do these squid need eyes the size of softballs? Life at depths of 3,000+ feet is pitch black, and these creatures face a very specific threat: sperm whales.

Research suggests those enormous eyes evolved specifically to detect the bioluminescent glow that sperm whales create as they swim through clouds of light-producing plankton. With eyes this large, colossal squid can spot a charging whale from over 400 feet away in near-total darkness—just enough time to attempt an escape.

The eye's massive lens gathers every available photon, turning faint glimmers into actionable intel. It's one of nature's most impressive adaptations to extreme environments.

Meet Both Giants

Giant squid (Architeuthis dux): Up to 43 feet long, 10-inch eyes, found worldwide in deep waters
Colossal squid (Mesonychoteuthis hamiltoni): Up to 46 feet long, 11-12 inch eyes, found in Antarctic waters

Both are extraordinary, elusive, and equipped with some of the most powerful vision systems on Earth. But when it comes to sheer eye size, the colossal squid takes the crown.

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